Flying blind with PFAS and pesticides

A cow, grazing at Eggersrieter Höhe in the canton of St Gallen. Some of the soil there is contaminated with PFAS, and the meat of these animals can exceed the limits allowed. | Photo: Gian Ehrenzeller / Keystone-SDA

It could have been a milestone in Swiss health research. In 2014, the Swiss Federal Office of Public Health (FOPH), in collaboration with the Swiss Biobanking Platform and several hospitals and universities, launched the ‘Swiss Health Study’. It was supposed to take at least 20 years, and would regularly analyse blood and urine samples from 100,000 volunteers aged between 20 and 69.

The research team responsible for it wanted to collect valuable data on the state of health and chemical exposure of the Swiss population, and to acquire a better understanding of how nutrition and lifestyle affect the development of diseases. A biobank was to have been established to store the samples on a long-term basis.

In 2020, a pilot study for it was initiated with almost 800 adults from the cantons of Bern and Vaud, the purpose being to test methods for the proposed large-scale, long-term study. It was also intended to establish the infrastructure that would be needed. In August 2023, the FOPH published the results of this pilot, revealing that its participants had been exposed to heavy metals, the pesticide glyphosate and PFAS chemicals, ‘Per- and polyFluoroAlkyl Substances’ – a group of several thousand synthetic, industrial chemicals that have been in large-scale use since the 1970s. To be sure, these substances were present in most participants at levels beneath the threshold that would be relevant to their state of health. But there were also significant instances where this threshold was exceeded.

In August 2025, the Federal Council issued a surprise statement cancelling the long-term study on grounds of it being too expensive. Its annual costs had been estimated at CHF 10 to 12 million, and that was more than Switzerland could afford at that time, they said.

77 times over the limit

Martin Scheringer is a lecturer at ETH Zurich who specialises in organic environmental chemistry, and he’s perplexed by the cancellation: “To put it bluntly, this decision was wrong, stupid and not evidence-based”. His research is focused on PFAS. High levels of exposure can increase the risk of cancer of the kidneys, breasts and testicles, and can reduce fertility. “A national cohort study would have given us a more precise idea of just how heavily the Swiss population has actually been exposed to PFAS”.

Scheringer can offer a concrete example of the benefits of such data. Last year, he was approached by an amateur angler who lives next to Lake Zug and regularly eats the fish he catches there. But he was worried about his health. Scheringer advised him to get his blood tested for the four most common PFAS. The result revealed 537 micrograms of perfluorooctane sulfonic acid (PFOS) per litre of blood. PFOS belongs to the PFAS group, and this amount is 77 times the limit that’s considered safe. “A national health cohort would enable us to identify individuals and large groups who are heavily contaminated with specific chemicals, and it would help us to pinpoint hotspots where that contamination occurs”, says Scheringer with conviction.

The FOPH pilot study also showed that PFOS poses a particular risk to public health because the health-relevant threshold was exceeded in almost four percent of its participants. Analysing blood and urine samples would allow the authorities to identify key sources of exposure to PFOS, whether these be contaminated vegetables, meat or fish. “This isn’t just some academic exercise”, says Scheringer. “With data like these, we could determine concrete protective measures for the overall population”.

A blow to the whole research sector

Nicole Probst-Hensch also finds it hard to understand the decision of the federal government. She’s an epidemiologist at the Swiss Tropical and Public Health Institute in Basel (Swiss TPH), and she played a significant role in developing the proposed national health study. “Cohorts that are monitored over many years are just as important to us as a well-equipped laboratory to someone engaged in basic research”, she says. “In the latter case, nobody asks whether they really need their lab”. What’s more, she says, it’s just not enough simply to measure chemical exposure in the environment, which is already being done today.

She’s referring to SAPALDIA (the Study on Air Pollution And Lung Disease In Adults), Switzerland’s longest-running cohort study on lung and heart diseases, which has been running since 1991. Over its various phases since then, it’s monitored up to 10,000 people. It has collected tens of thousands of biological samples in a biobank where they can be analysed in years to come, should researchers wish to answer specific questions. This study, says Probst-Hensch, has made a major contribution to a better understanding of risk factors such as air and noise pollution.

Furthermore, she says, it’s a prime example of the societal benefit of public health research: “We worked closely with FOEN (the Swiss Federal Office for the Environment), and they ultimately introduced a limit for air pollutants”. Ten years later, the cohort study was able to prove the positive impact of that decision.

This is also of inestimable value to Switzerland as a research hub, says Probst-Hensch: “Thanks to SAPALDIA, we’ve been able to procure millions in third-party funding and have participated in international studies”. But when colleagues from Germany today present genetic data and analyses from a cohort study launched in 2014 that involves more than 200,000 people, she asks herself: “What can Switzerland contribute?” She’s concerned that Swiss researchers are not keeping pace with international environmental projects or with research into prevention and treatment.

It’s already been noted several times that there’s a lack of long-term epidemiological data on health in Switzerland. In a report published in 2024, the Swiss Federal Finance Commission wrote: “We need a monitoring system that can provide representative data on problematic substances in all environmental media and in humans”. This is because exposure to such substances can pose a considerable risk to the national economy.

In response to our queries, even the FOPH confirmed that there’s a lack in this regard: “No nationally representative data currently exist on PFAS and pesticides”. To be sure, the FOPH remains interested in a national programme for human biomonitoring. But it’s unable to help fund it. All the same, the FOPH has offered expert support to any such initiative arising from the research community.

No data for an overview

Stephan Bohlhalter is head of the department of neurology and neurorehabilitation at the Lucerne Cantonal Hospital. Farmers regularly arrive at his surgery who are suffering from Parkinson’s disease. “It’s striking”, he says. But the data that he has collected are of only limited significance. “A national health study would allow us to draw representative conclusions that would be valid across different regions”. Parkinson’s is the fastest-growing neurological disease across the world, says Bohlhalter. Numerous international studies have meanwhile proven that exposure to pesticides increases the risk of developing it. In France and Germany, Parkinson’s has become acknowledged as an occupational disease among farmers.

Bohlhalter is the chairman of the expert advisory board of ‘Parkinson Switzerland’, which also means he has links to the political sphere. But he believes that few in Parliament today are actually interested in the possible health impact of pesticides, neither on those in exposed occupations, nor on the general public. On one of his visits to the Swiss Federal Parliament, one politician even told him that they’d already discussed the matter enough and that it wasn’t a priority any more. “So we now need pressure from the public and from the research community”, says Bohlhalter, “otherwise nothing’s going to change in terms of public health”.

The Swiss Farmers’ Union (SBV) sees no need for action regarding Parkinson’s disease. Its spokesperson responded to us as follows: “Farmers are more concerned about their economic situation than about their health”. Already today, they wrote, Parkinson’s can be recognised as an occupational disease in people “who are exposed to pesticides as part of their work”. They also referred to a small cohort study that has been conducted by Swiss TPH since 2022, involving almost 900 farmers. However, this study relies solely on questionnaires, with no samples taken and no associated biobank.

Hijacked by industry

As an environmental chemist, Martin Scheringer is in contact with the regulatory authorities of individual cantons. But he points out that there is no functioning interface for them at the federal level. “Politics isn’t evidence-based. It’s driven by vested interests”, he says, adding that he’s observed how financially powerful companies regularly try to influence the public debate on PFAS and pesticides and whether to regulate them. “The chemical industry has far better access to politicians than researchers do”, he says. In March 2026, the Council of States even decided that the review process for approving pesticides should be relaxed to support the agricultural sector.